docs: add docstring for the paginator property override

lms/djangoapps/mobile_api/users/views.py

@@ -385,6 +385,11 @@ class UserCourseEnrollmentsList(generics.ListAPIView):
     # pylint: disable=attribute-defined-outside-init
     @property
     def paginator(self):
+        """
+        Overrides API View paginator property to dynamically determine pagination class 
+        based on the provided api_version. Implements solutions from the discussion at 
+        https://www.github.com/encode/django-rest-framework/issues/6397.
+        """
         super().paginator  # pylint: disable=expression-not-assigned
         api_version = self.kwargs.get('api_version')